1A. The chair and the desk are being sold at the garage sale.
1B. At the garage sale, the chair and the desk are being sold.
The subordinate clause is: at the garage sale
The Independent clause is: the chair and the desk are being sold
Now, if the subordinate clause is at the beginning of the sentence a comma is needed at the end of the subordinate clause, for example, 1B.
If the subordinate clause is at the end of the sentence, a comma is not needed, for example 1A.
More examples:
2A Although we had prepared for emergency situation, we did not anticipate the number of people who would need supplies.
2B We did not anticipate the number of people who would need supplies although we had prepared for emergency situations.
As soon as the rain stops, we can go outside
We can go outside as soon as the rain stops.
Marissa took notes for Dallas when Dallas was sick.
When Dallas was sick, Marissa took notes for Dallas.
After the test, the students rejoiced and danced around the classroom.
The students rejoiced and danced around the classroom after the test.
1A. The chair and the desk are being sold at the garage sale.
1B. At the garage sale, the chair and the desk are being sold.
The subordinate clause is: at the garage sale
The Independent clause is: the chair and the desk are being sold
Now, if the subordinate clause is at the beginning of the sentence a comma is needed at the end of the subordinate clause, for example, 1B.
If the subordinate clause is at the end of the sentence, a comma is not needed, for example 1A.
More examples:
2A Although we had prepared for emergency situation, we did not anticipate the number of people who would need supplies.
2B We did not anticipate the number of people who would need supplies although we had prepared for emergency situations.
As soon as the rain stops, we can go outside
We can go outside as soon as the rain stops.
Marissa took notes for Dallas when Dallas was sick.
When Dallas was sick, Marissa took notes for Dallas.
After the test, the students rejoiced and danced around the classroom.
The students rejoiced and danced around the classroom after the test.